Big assembly with movable rig floor units

ABSTRACT

The invention relates to a rig assembly for use in the oil and gas exploration and production industry. In an embodiment of the invention, a rig assembly ( 12 ) for a drill ship ( 10 ) is disclosed. The rig assembly ( 12 ) comprises a rig floor receiving area ( 14 ); a plurality of movable rig floor units ( 18, 20, 22  and  24 ), each rig floor unit ( 18, 20, 22  and  24 ) configured for location in the rig floor receiving area ( 14 ), to thereby define a rig floor of the rig assembly ( 12 ); and a transporter ( 26 ) configured to receive any one of the rig floor units ( 18, 20, 22  and  24 ), for transporting a selected one of the rig floor units ( 18, 20, 22  and  24 ) from a storage area ( 28 ) to the rig floor receiving area ( 14 ).

The present invention relates to a rig assembly for use in the oil andgas exploration and production industry. In particular, but notexclusively, the present invention relates to a rig assembly with animproved rig floor, as well as to an improved rig floor, a transporterand a method of providing a rig floor of a rig assembly.

In the oil and gas exploration and production industry, access tosubterranean oil and gas reserves is typically achieved by drilling awell from surface and installing and cementing a series of concentriccasing strings in the drilled borehole, extending from a wellhead. Theborehole is then extended to a desired depth and a liner installed inthe extended section, the liner extending from the bottom or ‘shoe’ ofthe lowermost casing string. Following cleaning and testing of the linedborehole, production tubing is installed extending from surface downthrough the casing and liner to a producing formation. Well fluids flowinto the production tubing from the formation and are thereby recoveredto surface.

In an offshore environment, it is necessary to install a large diametertubing, known as a riser, extending from the wellhead to a surfacefacility such as a drillship, floating production storage and offloadingvessel (FPSO), drilling rig or the like. Tubing strings including liner,drill strings, production tubing and other intervention or tool stringsare all run into the borehole through the riser. A blow-out preventer(BOP) is also provided as part of the riser string, and is eitherlocated at seabed level on the wellhead, or is located nearer tosurface, if prevailing weather conditions permit. As is well known inthe art, the BOP permits safe shut-down of the well in the event of anemergency situation arising.

Other types of procedures have been proposed for gaining access to wellfluids, including the method proposed by one of the present co-inventorsin International Patent Application No. PCT/GB2005/002885, whereby asubsea shut-off device including a ball gripping mechanism is latched toa template at surface, and drilled in casing is suspended from thedevice at any position using the gripping mechanism so that the deviceis run to the sea floor on a casing string. The casing string is drilledinto place and converted into a riser, and this is all done on a singletrip to speed up the operation and reduce risk. The casing string iscaptured and sealed within the subsea shut-off device after installingand spacing out a surface BOP.

A vast array of equipment is required in order to bring a well intoproduction, whether following conventional techniques, or alternativessuch as that proposed in PCT/GB2005/002885. Much of the equipmentutilised must be brought to a location adjacent a rig floor of thesurface facility, for subsequent deployment, or is deployed from a levelbelow the rig floor. Conventionally, this has been achieved utilisinghandling equipment including cranes, elevators and the like. In morerecent years, dedicated equipment has been developed specifically forhandling apparatus to be deployed from the rig, particularly large,heavy apparatus such as BOPs, which may weigh several hundred tonnes.

The handling of equipment utilising cranes and elevators is generallyundesired, and can lead to accidents, particularly on vessels which aresubject to relatively large movements under applied wind, wave and tidalloading. Additionally, the handling of apparatus using such equipment istypically time-consuming and laborious. It will be appreciated that, inview of the high rental costs involved in leasing offshore equipmentsuch as floating rigs and drillships, it is generally desired tominimise the time taken to carry out all types of procedure in theindustry.

Where dedicated equipment has been provided for handling apparatus to bedeployed, this equipment has conventionally been very large, whichpresents a particular problem in the offshore environment, where spaceis severely restricted. Additionally, the handling equipment is suitedonly for a single use or purpose; is typically slow moving; and is notcapable of being used to handle other types of apparatus.

Whilst space restrictions are less pronounced in onshore facilities, itwill be understood that many of the above problems are of equal concern.

It is amongst the objects of embodiments of the present invention toobviate or mitigate at least one of the foregoing disadvantages.

According to a first aspect of the present invention, there is provideda rig assembly comprising:

-   -   a rig floor receiving area;    -   a plurality of movable rig floor units, each rig floor unit        configured for location in the rig floor receiving area, to        thereby define a rig floor of the rig assembly; and    -   a transporter configured to receive any one of the rig floor        units, for transporting a selected one of the rig floor units        from a storage area to the rig floor receiving area.

It will be understood that the transporter may also be for transportinga rig floor unit from the rig floor receiving area to the storage area,when it is desired to locate an alternative selected rig floor unit inthe rig floor receiving area. The transporter may therefore serve fortransporting rig floor units between the two areas.

It will also be understood that a rig floor of a rig assembly isgenerally defined as the work area in which a rig crew conductsoperations.

Providing a rig assembly with a plurality of movable rig floor units, arig floor receiving area, and a transporter for transporting a selectedrig floor unit from a storage area to the rig floor receiving area,facilitates a rapid changeover at the rig floor area when differenttasks or operations are to be performed, when compared with priorpractice in the industry.

Each rig floor unit may be adapted for performing a different task oroperation or a step in a task or operation. Thus switching of equipmentnecessary to carry out the desired task, operation or step may berapidly achieved simply by switching around the rig floor units. Tofacilitate this, each rig floor unit may be adapted to carry differentequipment suited to the particular task, operation or step.

The storage area may comprise a plurality of rig floor storagelocations, each configured to receive a respective rig floor unit.Accordingly, each rig floor unit may be adapted to be located in arespective storage location in the storage area. The selected rig floorunit may be adapted to be transferred from its storage location on tothe transporter, which may then transport the rig floor unit to the rigfloor receiving area.

The transporter may be movable along a path extending between thestorage area and the rig floor receiving area, for transporting the rigfloor units between the storage area and the rig floor receiving area.The transporter may therefore be movable to a position where it canaccess any one of the rig floor units, such that the selected rig floorunit may be transferred on to the transporter, and such that a rig floorunit returned from the rig floor receiving area to the storage area bythe transporter may be transferred off the transporter. The rig floorunits may each be configured to be releasably secured, locked or locatedrelative to or within the transporter. This may permit safetransportation of the rig floor units between the storage area and thereceiving area, as well as safe operation in use of the rig floordefined by the rig floor unit. One or both of the rig floor units andthe transporter may comprise a locking assembly for securing the rigfloor units relative to the transporter. The transporter may beconfigured to be releasably secured, locked or located relative to orwithin the rig floor receiving area. In this fashion, the transporter,carrying the selected rig floor, may be secured within the rig floorreceiving area and may thereby locate the rig floor unit in thereceiving area, to define the rig floor. It will therefore be understoodthat the transporter may remain within the receiving area during thetime when the selected rig floor unit is in the receiving area.

The transporter may be configured to be secured to a support structureprovided in the rig floor receiving area. One or both of the transporterand the support structure may comprise a locking assembly for securingthe transporter in the receiving area. The locking assembly may compriseat least one, and preferably a plurality of locking dogs, pins, latchesor the like. The locking assembly may be hydraulically actuated, or inalternative embodiments, may be electro-mechanically or electricallyactuated or a combination thereof.

In alternative embodiments, the rig floor units may each be configuredto be releasably secured, locked or located relative to or within therig floor receiving area. In this fashion, the transporter may beremoved from the receiving area, if desired, following location of therig floor unit within the rig floor receiving area.

The rig floor units may be configured to be secured to a supportstructure provided in the rig floor receiving area. One or both of therig floor units and the support structure may comprise a lockingassembly for securing the rig floor units in the receiving area. Thelocking assembly may comprise at least one, and preferably a pluralityof locking dogs, pins, latches or the like. The locking assembly may behydraulically actuated, or in alternative embodiments, may beelectro-mechanically or electrically actuated or a combination thereof.

The rig assembly may comprise a transfer system for transferring the rigfloor units between a storage location within the storage area and thetransporter. The transfer system may comprise a translation device fortranslating the rig floor units between their storage locations and thetransporter. The translation device may be adapted to transfer the rigfloor units directly between their respective storage locations and thetransporter. However, in embodiments of the invention, the transfersystem may comprise a lift, elevator or the like for raising and/orlowering the rig floor units between a level of the storage locationsand a level of the transporter. In use, a rig floor unit may betranslated on to the lift and the lift may then raise or lower the rigfloor unit into a position where the unit may be received within thetransporter. The transporter may be shaped to define a space in whichthe rig floor units are received, to facilitate transfer of the unitsfrom the lift into the transporter. In particular, the transporter maybe shaped to straddle the rig floor units, and may comprise first andsecond sides spaced and connected by a connecting structure, with aspace defined between the sides in which the rig floor units arereceived. In a variation, the transporter may be height adjustable forraising and lowering to a level of the unit storage locations.

The rig assembly may be modular and may therefore be adaptable forvarious different types of rig, according to the space available.Accordingly, the rig assembly may be configured as required to suit aparticular rig.

The rig assembly may comprise handling equipment which may be coupled toand movable with the transporter, or which may be independently movablerelative to the transporter. The handling equipment may comprise atubing handling device for picking up and/or supporting a length oftubing, and which may serve for transferring tubing on to thetransporter. This may facilitate subsequent deployment of the tubing onto and/or through the rig floor defined by the selected rig floor unit.It will be understood that the tubing may be a length of casing, liner,riser, drill tubing, production tubing or any other tubing utilised inthe industry. The handling device may comprise one or moreelectromagnetic supports for selectively picking up and/or supportingthe tubing. The handling device may be adapted to incline the tubing toassist in transfer on to the rig floor, and may comprise a support forsupporting an end of the tubing during transfer.

The rig floor receiving area may be adapted to be provided on or in adeck of a surface facility on which the rig assembly is provided. Therig floor receiving area may be provided around or adjacent to amoonpool in the facility. It will be understood that the moonpool is theopening in the hull or structure of the surface facility through whichequipment/apparatus passes. The transporter may be for transporting theselected rig floor unit to a location above the moonpool, for thedeployment of equipment into the moonpool. It will be understood thatthe surface facility may be a vessel such as a drillship, FPSO or FSO,or a rig such as a semi-submersible, submersible or jack-up rig.Alternatively, the rig floor receiving area may be adapted to beprovided on or in a frame or support which may extend overboard.

The rig floor units may each comprise handling apparatus for handlingequipment to be deployed from the rig floor. The rig floor units may beselected from a group comprising: a drill unit having a rotary drive fordriving and rotating a string of tubing; a BOP unit for supporting aBOP; a coiled tubing injector unit for supporting a coiled tubinginjector to be used for running coiled tubing; and a subsea shut-offdevice unit, for running a subsea shut-off device such as that disclosedin International Patent Application No. PCT/GB2005/002885. However, itwill be understood that, in principle, any desired rig floor unit may beprovided. At least one of the rig floor units may be adapted fordeploying equipment from the rig assembly. For example, in embodimentsof the invention, at least one of the rig floor units may comprise anaperture through which equipment may be deployed.

At least one of the rig floor units may be adapted to selectivelysupport a tubing string and may therefore serve for suspending at leastpart of the load of a tubing string from the rig. The rig assembly maycomprise a support for supporting a load of a tubing string duringchangeover of rig floor units.

If desired, the transporter may be configured to receive a plurality ofselected rig floor units. Thus, for example, where the rig assemblycomprises three or more rig floor units, the transporter may beconfigured to receive two units, for faster changeover.

The transporter may be self-driven, and may therefore comprise a drivesystem for moving the transporter between the storage area and the rigfloor receiving area. The drive system preferably comprises a pluralityof drive wheels which are adapted to run on guide rails, but mayalternatively comprise wheels, tracks or the like.

According to a second aspect of the present invention, there is provideda movable rig floor unit, the rig floor unit configured for location ina rig floor receiving area of a rig assembly to thereby define a rigfloor of the rig assembly, the rig floor unit further configured to bereceived in a transporter for transportation from a storage area to therig floor receiving area.

According to a third aspect of the present invention, there is provideda rig floor transporter, the transporter configured to receive any oneof a plurality of rig floor units, for transporting a selected one ofthe rig floor units from a storage area to a rig floor receiving area ofa rig assembly.

Further features of the rig floor unit and the transporter of the secondand third aspects of the invention, respectively, are defined above inrelation to the first aspect of the invention.

According to a fourth aspect of the present invention, there is provideda rig comprising a rig assembly according to the first aspect of thepresent invention.

According to a fifth aspect of the present invention, there is provideda vessel comprising a rig, the rig comprising a rig assembly accordingto the first aspect of the present invention.

According to a sixth aspect of the present invention, there is provideda method of providing a rig floor of a rig assembly, the methodcomprising the steps of:

-   -   providing a plurality of movable rig floor units, each rig floor        unit configured for location in a rig floor receiving area of a        rig assembly, the rig floor units located in a storage area on a        rig;    -   selecting one of the rig floor units;    -   mounting the selected rig floor unit on a transporter configured        to receive any one of the rig floor units;    -   transporting the selected rig floor unit from the storage area        to the rig floor receiving area using the transporter; and    -   locating the selected rig floor unit in the rig floor receiving        area, to thereby form a rig floor of the rig assembly.

Preferably, the method further comprises the steps of:

-   -   returning the selected rig floor unit from the rig floor        receiving area to the storage area using the transporter;    -   selecting an alternative rig floor unit;    -   mounting the alternative rig floor unit on the transporter;    -   transporting the alternative rig floor unit from the storage        area to the rig floor receiving area using the transporter; and    -   locating the alternative rig floor unit in the rig floor        receiving area, to thereby form an alternative rig floor of the        rig assembly. These steps may be repeated as necessary or as        desired in order to define a number of different rig floors,        which may permit a range of operations to be carried out.        Indeed, the method may further comprise the steps of performing        an operation or a step in an operation from the rig floor        defined by the selected rig floor unit, before returning the        unit to the storage area and, following location of the        alternative unit in the receiving area, performing an operation        or a further step in an operation from the alternative rig        floor.

The method may comprise securing the selected rig floor unit relative tothe transporter, transporting the selected rig floor unit to thereceiving area and securing the transporter within the receiving area.An operation or step in an operation may then be carried out from therig floor. Alternatively, the selected rig floor unit may be securedwithin the receiving area and the transporter moved away from thereceiving area.

The rig floor units may be stored in respective rig floor unit storagelocations within the storage area, and may be transferred on to thetransporter by a transfer system. The storage locations may be at alevel above or below that of the transporter, therefore the method maycomprise lowering or raising the units from their respective storagelocations to the level of the transporter, for transferring the units onto the transporter.

According to a seventh aspect of the present invention, there isprovided a rig assembly comprising:

-   -   a rig floor receiving area;    -   a plurality of movable rig floor units, each rig floor unit        configured for location in the rig floor receiving area, to        thereby define a rig floor of the rig assembly; and    -   a transporter configured to receive any one of the rig floor        units, for transporting a rig floor unit between a storage area        and the rig floor receiving area.

Embodiments of the present invention will now be described, by way ofexample only, with reference to the accompanying drawings, in which:

FIGS. 1 and 2 are plan and side views respectively, of a vesselincorporating a rig assembly, in accordance with an embodiment of thepresent invention;

FIG. 3 is an enlarged plan view of the rig assembly shown in FIGS. 1 and2;

FIG. 4 is an enlarged side view of part of the rig assembly shown inFIGS. 1 and 2;

FIGS. 5 and 6 are enlarged plan and side views, respectively, of atransporter forming part of the rig assembly shown in FIGS. 1 and 2;

FIGS. 7 and 8 are enlarged plan and side views, respectively, of a firstrig floor unit forming part of the rig assembly shown in FIGS. 1 and 2;

FIGS. 9 and 10 are enlarged plan and side views, respectively, of asecond rig floor unit forming part of the rig assembly shown in FIGS. 1and 2;

FIGS. 11, 12 and 13 are enlarged plan, side and further side views,respectively, of a third rig floor unit forming part of the rig assemblyshown in FIGS. 1 and 2;

FIGS. 14, 15 and 16 are enlarged plan, side and further side views,respectively, of a fourth rig floor unit forming part of the rigassembly shown in FIGS. 1 and 2;

FIGS. 17 and 18 are enlarged plan and side views of handling equipmentforming part of the rig assembly shown in FIGS. 1 and 2;

FIGS. 19 to 24 are schematic side views illustrating use of the handlingequipment shown in FIGS. 17 and 18;

FIGS. 25, 26 and 27 are enlarged plan, side and end views, respectively,of a tail loader provided on the transporter shown in FIGS. 1 to 6;

FIG. 28 is a perspective view of part of a support frame, forming partof a rig assembly in accordance with an alternative embodiment of thepresent invention; and

FIG. 29 is a perspective view of a tubing gripping assembly forming partof the support frame shown in FIG. 28.

Turning firstly to FIGS. 1 and 2, there are shown plan and side views,respectively, of a vessel in the form of a drillship 10 incorporating arig assembly indicated generally by reference numeral 12, in accordancewith an embodiment of the present invention. The rig assembly 12 isshown in more detail in the enlarged plan view of FIG. 3 and comprises arig floor receiving area 14 formed in a deck 16 of the drillship 10, anda plurality of moveable rig floors, decks or deck units 18, 20, 22 and24 which are initially spaced from the rig floor receiving area 14. Eachof the rig floor units 18, 20, 22 and 24 are configured for location inthe rig floor receiving area 14, to thereby define a rig floor of therig assembly 12. The rig assembly 12 also includes a transporter 26,which is shown in more detail in the enlarged side view of FIG. 4,showing part of the rig assembly 12, and in the enlarged plan and sideviews of FIGS. 5 and 6, respectively. The transporter 26 is configuredto receive any one of the rig floor units 18, 20, 22 and 24, fortransporting a selected one of the rig floor units 18, 20, 22 and 24from a storage area 28 (FIGS. 1 to 4) to the rig floor receiving area14.

The rig assembly 12 is shown in the Figures with all of the rig floorunits 18, 20, 22 and 24 in respective storage locations 30, 32, 34 and36 in the storage area 28 and thus prior to transportation of a selectedone of the rig floor units from the storage area 28 to the rig floorreceiving area 14.

A ram rig 38 is provided in the rig floor receiving area 14 above amoonpool 40 (FIGS. 1 and 3) extending through a hull 41 of the drillship10. The ram rig 38 serves for suspending tubing strings from thedrillship 10 and for running equipment downhole. It will be understoodthat a conventional derrick (not shown) may be provided in place of theram rig 38, if desired. As shown particularly in FIGS. 1 and 3, an upperend 42 of the moonpool 40 is open prior to location of a selected one ofthe rig floor units 18, 20, 22 or 24 above the moonpool 40.

As will be described in more detail below, each of the rig floor units18, 20, 22 and 24 are designed for carrying out different operations, ordifferent steps in an operation, and carry various different types ofequipment suited to the particular operation to be carried out. Byproviding rig floor units 18, 20, 22 and 24 suited for such differentoperations, the different operations or steps can be carried out bytransporting the desired rig floor unit from the storage area 28 to therig floor receiving area 14 to a position above the moonpool 40, tothereby define a rig floor of the rig assembly 12. Once located in thereceiving area 14, the desired operation or steps are carried out and,following completion of the operation, the selected rig floor unit 18,20, 22 or 24 may then be returned from the rig floor receiving area 14to the storage area 28 and an alternative rig floor unit selected andtransported to the rig floor receiving area 14. This alternative rigfloor unit 18, 20, 22 or 24 is then located above the moonpool 40 todefine a different rig floor, and permits an alternative operation, or afurther step in an operation, to be carried out.

The present invention therefore offers significant advantages overconventional procedures where apparatus required for conductingdifferent operations must be separately transported to the rig floorreceiving area using handling equipment such as cranes and elevatorsand, in certain-circumstances, specialised handling equipment suitedonly for the particular apparatus to be transported. As described above,such procedures are time-consuming and laborious. In contrast, it isanticipated that changeover of a rig floor unit 18, 20, 22 or 24 inplace above the moonpool 40 with an alternative rig floor unit will takearound 15 minutes to complete, and the operation will offer significantadvantages in terms of safety when compared to conventional handlingmethods using cranes, elevators and the like.

The rig assembly 12 and method of providing a rig floor of the rigassembly 12 will now be described in more detail.

The rig floor units 18, 20, 22 and 24 are shown in more detail in theviews of FIGS. 7 to 16. Of these, FIGS. 7 and 8 are enlarged plan andside views of the rig floor unit 18; FIGS. 9 and 10 are enlarged planand side views of the rig floor unit 20; FIG. 11 is an enlarged planview of the rig floor unit 22, whilst FIGS. 12 and 13 are enlarged sideviews of the unit 22 shown before and during deployment of BOP assembly;and FIG. 14 is an enlarged plan view of the rig floor unit 24 whilstFIGS. 15 and 16 are enlarged side views of the unit 24 prior to andduring deployment of a subsea shut-off device of the type disclosed inInternational Patent Application Number PCT/GB2005/002885.

As shown in FIGS. 7 and 8, the rig floor unit 18 comprises a frame 48and a deck surface 50 provided on the frame 48. An aperture 52 extendsthrough the deck surface 50, and handling equipment in the form of asupport structure 54 for a coiled tubing injector 56 is provided on theframe 48. It will therefore be understood that the rig floor unit 18comprises an injector deck. When the injector deck 18 is provided in thereceiving area 14 above the moonpool 40, the injector deck 18 defines arig floor which supports the coiled tubing injector 56 and permitsrunning and control of coiled tubing through a guide 58 (indicated inbroken outline), fed from a reel 60 shown in FIGS. 1 and 2.

As shown particularly in FIGS. 4 to 6, the transporter 26 includeshydraulically actuated lock-down pins or cylinders 62 which, onactuation, are movable between retracted and extended positions. Thepins 62 are shown in FIG. 5 in an extended position where the pinsengage lock-down tubes 64 mounted on the frame 48 of the injector deck18. The lock-down pins 62 and lock-tubes 64 together form part of alocking assembly for securing the injector deck 18 relative to thetransporter 26. The transporter 26 also comprises two side frame members66, 68, coupled by a connecting gantry 67. A space 70 is defined betweenthe side frame members 66 and 68 which is sized to receive the injectordeck 18. It will therefore be understood that when the injector deck 18is located within the space 70 and locked by the pins 62, thetransporter 26 may safely transport the injector deck 18 from thestorage area 28 to the rig floor receiving area 14.

The rig assembly 12 also includes a transfer system, best shown in FIG.3, which is indicated generally by reference numeral 72. The transfersystem 72 serves for transferring the selected rig floor unit 18, 20, 22or 24 from its respective storage location 30, 32, 34 and 36 onto thetransporter 26, and also for returning the respective rig floor unitfrom the transporter 26 to its storage location. To achieve this, thetransfer system 72 includes a lift 74 which can be raised and lowered.The lift 74 is positioned along a length of a path 76 which thetransporter 26 traverses during transportation of rig floor unitsbetween the storage area 28 and the rig floor receiving area 14. Thetransfer system 72 also includes two lateral (thwartships) translationassemblies 78 and 80, which serve for translating selected rig floorunits in the direction X-X′ (FIG. 3) and onto the lift 74 by virtue ofrespective lateral drives 82, 84. The lateral translation assemblies 78and 80 also include bow-stern drives 86, 88 for translating the rigfloor units in the direction of the arrows Y-Y′. The drives 82, 84 and86, 88 each take the form of conveyors of a conventional type.

Further, similar translation assemblies 90, 92 and 94 are provided whichinclude bow-stern drives 96, 98 and 100, respectively. It will thereforebe understood that the rig floor units 18, 20, 22 and 24 may be movedaround the storage locations 30, 32, 34 and 36 in the storage area 28,for positioning a desired rig floor unit adjacent the lift 74 and thusfor transferring the selected unit onto the lift 74.

Returning now to FIGS. 9 and 10, where the rig floor unit 20 is shown,the unit 20 takes the form of a drill deck suitable for drilling a wellbore and includes a rotary table 102. Like components of the drill deck20 with the injector deck 18 share the same reference numerals, with theaddition of the suffix a. The rotary table 102 is of a conventionaltype, save that the table 102 is moveably mounted within the deck 50 a.This facilitates deployment of apparatus through the deck 50 a, ifdesired, and enables a string of tubing (not shown) to be supported bythe ram rig 38 and/or a compensated support frame 104 (FIGS. 1 and 2),which will be described in more detail below. Lock-down tubes 64 a areprovided integrally within the frame 48 a.

Returning to FIGS. 11 to 13, where the rig floor unit 22 is shown, theunit 22 takes the form of a BOP deck. Like components of the BOP deckwith the injector deck 18 share the same reference numerals, with theaddition of the suffix b. A BOP support structure 54 b on a frame 48 bof the BOP deck 22 serves both for supporting the BOP 44, and forraising and lowering the BOP 44 by virtue of a deployment cylinder 106of the ram rig 38, for lowering the BOP 44 through the aperture 52 b andinto the moonpool 40. This facilitates coupling of tubing (not shown) tothe BOP 44, for deploying the BOP 44 from the drillship 10. Typically, afirst tubing section is suspended from the ramrig 38 and coupled to theBOP 44. The BOP 44 and first tubing section are then lowered downthrough the BOP deck aperture 52 b and through the support frame 104,and the BOP 44 is positioned below the frame 104. Following theteachings of PCT/GB2006/001822 to one of the present co-inventors, thedisclosure of which is incorporated herein by way of reference, the BOPis suspended from the frame 104 by a tubing gripper device on the frame,an example of which will be described in more detail below.

With the BOP 44 suspended below the support frame 104, the BOP 44 islowered through the moonpool 40 and from the drillship 10 towards aseabed. Successive tubing sections are coupled together to end-to-end ina fashion known in the art, to progressively extend the tubing string.This is achieved by lowering the frame 104 out of the moonpool 40;suspending the tubing string and BOP 44 from the deck 50 b using slipsor the like (not shown); releasing the gripping device on the frame 104from the tubing; and stripping the frame 104 back along the tubing upthe moonpool 40. The tubing string/BOP 44 is then once again supportedfrom the frame 104 using the gripping device, the slips released and thetubing/BOP 44 lowered a further distance. Additional tubing, suspendedfrom the ramrig 38, is then coupled to the tubing section extending upthrough the moonpool 40, and the tubing string/BOP 44 lowered a furtherdistance. This process is repeated until the BOP 44 has been deployeddown to the seabed and connected to a wellhead.

In accordance with the teachings of PCT/GB2006/001822, the support frame104 forms part of a compensating system for compensating movement of thedrillship 10 relative to the seabed, and can be operated in both activeand passive compensation modes.

Returning now to FIGS. 14 to 16, where the rig floor unit 24 is shown,the unit 24 takes the form of a deck for deploying the subsea shut-offdevice 46, and like components of the deck 24 with the injector deck 18share the same reference numerals, with the addition of the suffix c. Asupport structure 54 c supports the shut-off device 46 duringtransportation, in the position shown in FIG. 15, and this also permitsaccess to the device 46 for maintenance purposes. When the device 46 isto be deployed into the moonpool 40, the device 46 is rotated to theposition shown in FIG. 16 and is suspended from the ram rig 38. Thedevice 46 is then released from the support structure 54 a, tubing (notshown) coupled to the shutoff device 46, and the deck 50 c released fromthe receiving area 14 and removed from its position above the moonpool40, using the transporter 26. The shutoff device 46 is then loweredthrough the moonpool 40 to a position below the support frame 104, andis suspended from the frame 104 using a gripping device. The deck 50 ccan then be returned above the moonpool 40, and the shutoff device 46deployed from the drillship 10 with the assistance of slips or the likeon the deck 50 c, in the fashion described above in relation to the BOP44 of FIGS. 11 to 13.

Returning once more to FIGS. 4 to 6, it will be noted that thetransporter 26 includes transporter lock-down pins 108, which arehydraulically actuated in a similar fashion to the pins 62. Thetransporter pins 108 are shaped for engaging lock-down tubes 110provided in deck areas 112, 114, which thereby form support structuresfor the transporter 26. The transporter 26 is mounted for movement alonga pair of guide rails and includes powered track runners 118 (FIG. 6)for moving the transporter 26 along the rails 116.

The rig assembly 12 is operated to bring a selected rig floor unit 18,20, 22 or 24 to the rig floor receiving area 14 as follows. Initially,each of the units 18, 20, 22 and 24 are located in their respectivestorage locations 30, 32, 34 or 36 and the transporter is in theposition shown in FIGS. 1 to 4. In a first procedure, it is desired tolocate the drill deck 20 above the moonpool 14. This is achieved byraising the lift 74 up to the level of the drill deck 20 (FIG. 4) andtranslating the drill deck 20 from its storage location 32 using thelateral drives 82. It will be noted that the lift 74 includes similardrives 120 for positioning the drill deck 20 on the lift. The lift 74then lowers the drill deck 20 to the level of the lock-down pins 62 onthe transporter 26, and the transporter 26 is driven along the guiderails 116 to a position were the drill deck 20 is received within thespace 70, with the drill deck lock-down tubes 64 in alignment with thepins 62. This movement is permitted by virtue of the connecting gantry67 of the tranporter 26, which passes over the top of the drill deck 20.However, it will be understood that where larger equipment, such as theBOP assembly 44, has to be carried by the transporter 26, it may benecessary for the lift 74 to carry the BOP assembly 44 further down into the hull 41 of the drillship 10, and then to raise it up followingpositioning of the transporter 26.

With the drill deck 20 in position, the lock-down pins 62 are actuated,engaging in the tubes 64, and the drill deck 20 is then locked andsecured relative to the transporter 26. The transporter 26 is thenreturned along the guide rails 116, and moves to a position where thedrill deck 20 is above the moonpool 40, with the transporter lock-downpins 108 aligned with the transporter lock-down tubes 110. The pins 108are then actuated, to lock and secure the transporter 26 within the rigfloor receiving area 14. This therefore secures the drill deck 20 withinthe receiving area 14, and the drill deck 20 now forms the rig floor.

Following completion of a drilling procedure utilising the drill deck20, it is desired to return the drill deck 20 to the storage area 28 andto select an alternative rig floor unit from the injector deck 18, BOPdeck 22 and shut-off device deck 24. To achieve this, the transporterlock-down pins 108 are disengaged, and the transporter returned to aposition where the drill deck 20 is above the lift 74. The lift 74 isthen raised to bear the load of the drill deck 20, and the lock-downpins 62 disengaged. The transporter 26 is then translated back along theguide rails 116, and the drill deck 20 returned to the storage location32, utilising the lift drives 120 and the lateral drives 82. If it isnow desired to transfer the injector deck 18 from its storage location30 to the receiving area 14, the drill deck 20 is firstly transferred toa holding storage location 122 by the bow-stern drives 86 on thetranslation assembly 78, and the injector deck 18 is then transferred onto the lateral translation assembly 78 by the bow-stern drives 96 on theassembly 90. The injector deck 18 is then transferred on to the lift 74,and secured to the transporter 26 before being carried to the receivingarea 14 and secured as described above. Following completion of aprocedure utilising the injector deck 18, the injector deck 18 isreturned to the storage location 30 in a similar fashion to the drilldeck 20, and the BOP deck 22 or shut-off device deck 24 may then becarried to the receiving area 14 in the fashion described.

The rig assembly 12 additionally includes tubing handling equipment inthe form of a casing car, which is shown in the enlarged plan and sideviews of FIGS. 17 and 18, respectively, and indicated generally byreference numeral 124. The casing car 124 is self-driven, in a similarfashion to the transporter 26, but is powered and controlled by thetransporter 26 and connected by an umbilical or the like (not shown).

The casing car 124 includes a lifting arm 126 which is pivotally mountedto a beam 128, the beam 128 being driven and rotatable about an axis 132relative to the frame 130. Additionally, the beam 128 can be drivenalong the length of a cross-frame arm 133. The lifting arm 126 carries apair of electromagnets 134 which, when actuated, collect a casingsection 136 from a store 138 on the deck 16. Lifting of the casingsection 136, deployment onto the transporter 26 and thus onto the rigfloor is shown in the schematic views of FIGS. 19 to 24. The lifting arm126 is initially positioned relative to the casing section 136 to belifted such that the section 136 lies horizontally when lifted, onrotation of the beam 128. The support arm 140 carries a bucket 142which, when in the position indicated by broken outline in FIG. 18,inclines the casing section 136 from the horizontal, to facilitatetransfer of the casing section 136 from the casing car 124 on to thetranporter 26. The support arm 140 is also rotatable to the positionshown in solid outline in FIG. 18, where the bucket 142 forms a supportfor an end 144 of the casing section 136. Following movement to theposition shown in FIG. 24, the casing section 136 is vertical and readyfor deployment utilising the ram rig 38.

To assist in deployment of the casing section 136, a tail loader 146 isprovided in the transporter 26 and is shown in more detail in the plan,side and end views, respectively, of FIGS. 25 to 26. The tail loader 146includes a V-ramp 148 for receiving the casing section 136, and a pairof arms 150 which are mounted to the V-ramp and which carry a roller152. As shown in FIG. 27, the roller 152 tapers towards a centralsection 154 which co-operates with the V-ramp 148 to support the casingsection 136. As shown particularly in FIGS. 22 to 24, the arms 150 arerotatable in the direction of the arrow Z (FIG. 26), to bring the roller150 into contact with the casing-section 136 and to support the casingsection safely during deployment into the ram rig 38, and indeed duringdeployment through the moonpool 40.

Considering now the support frame 104 in more detail, the support frame104 includes a leader frame 156 which is supported on a tension frame158. The leader frame 156 is movable within the moonpool 40 and locksout towards a lower end 160 of the moonpool, whilst the tension frame158 can be deployed into the water below the drillship 10, following theteachings of PCT/GB2006/001822. Four arms 162, best shown in FIG. 3, arepivotally coupled to the tension frame 158 and, in the position of FIG.3, provide a mounting for the gripper device (not shown). When it isdesired to have full access down the moonpool 40 through the tensionframe 158, the gripper device is removed from its location on the arms162, and the arms pivoted to folded positions. This providesunrestricted passage through the tension frame 158, for example, for theBOP 44.

Turning now to FIG. 28, there is shown a perspective view of part of analternative support frame 104′. Like components of the support frame104′ with the support frame 104 share the same reference numerals, withthe addition of the suffix ′. Only the differences between the frames104′ and 104 will be described herein in detail.

FIG. 28 in fact shows a tension frame 158′ of the support frame 104′.The tension frame 158′ includes four main columns 164, each of whichcarries a respective inwardly extending lug or boss 166. These lugs 166are provided in place of the pivoting arms 162 of the frame 104, andprovide mountings for a tubing gripping assembly 168, which is shown inthe perspective view of FIG. 29. The gripping assembly 168 includes areleasable gripper device 170, and is shown gripping and supportingtubing in the form of a drill collar 172. The gripper device 170 isprovided within a central hub 174, from which four mounting arms 176extend. Each of the mounting arms 176 include a pair of shaped wedges178, which are shaped to engage around the lugs 166, such that thegripping assembly 168 can be releasably mounted on the lugs 166 and thuslocated within the tension frame 158′. The gripping assembly 168 can beselectively removed from its location within the tension frame 158′ whenfull clearance through the support frame 104′ is required, for example,for the passage of the BOP 44, simply by lifting the assembly 168 up offthe lugs 166. Following passage of the BOP 44 through the support frame104′, the gripping assembly 168 can be returned to its position withinthe tension frame 158′.

The gripper device 170 includes a pair of hinged gripper arms 180, eachof which carries a half-cylindrical slip or tubing grip 182. The arms180 are pivotally mounted to the hub 174 by pins 181, and are movedbetween disengaged and engaged positions by hydraulic pistons 184. Thearms 180 are shown in FIG. 29 in their engaged positions, where theslips 182 are seated in an upper end of a bore of a hollow mounting 186which is located within the hub 174, defining a cylindrical collar. Theslips 182 are each shaped to engage an upset or shoulder on the drillcollar 172, for suspending a tubing string including the drill collar172 from the tension frame 158′. To release the drill collar 172, thepistons 184 are actuated to rotate the slips 182 away from the upper endof the mounting 186 bore. It will be understood that this facilitatesrelease of the tension frame 158′ from the tubing string, such that theframe 158′ may be stripped along the tubing for coupling further tubingsections, such as a further drill collar 172.

Movement of the tension frames 158, 158′ is controlled using winches andtensioner devices according to the teachings of PCT/GB2006/001822. In anactive compensation mode, movement of the tension frame 158 or 158′ iscontrolled such that the location of equipment relative to a seabed isprecisely controlled during deployment of the equipment from thedrillship 10. This is particularly important, for example, duringlowering of a tubing string carrying the BOP 44 where the drillship 10is pitching, rolling and heaving under applied wind, wave and tidalloads. In a passive compensation mode, movement of the tension frame 158or 158′ relative to the drillship 10, due to movement of the drillship10, is damped out using the winches and tensioner devices.

The rig assembly described herein, including the rig floor units 18-24,transporter 26 and support frame 104 offers particular advantages inthat the load of tubing/equipment can be transferred between the frame104 and the drillship 10 deck, facilitating changeout of the deck units.

Various modifications may be made to the foregoing without departingfrom the spirit and scope of the present invention.

For example, the locking assemblies may comprise locking dogs, latchesor the like. The locking assemblies may be hydraulically actuated,electro-mechanically or electrically actuated, or indeed a combinationthereof.

The rig floor units may each be configured to be releasably secured,locked or located relative to or within the rig floor receiving area. Inthis fashion, the transporter may be removed from the receiving area, ifdesired, following location of the rig floor unit within the rig floorreceiving area.

The translation devices may be adapted to transfer the rig floor unitsdirectly between their respective storage locations and the transporter.

The transporter may be height adjustable for raising and lowering to alevel of the unit storage locations.

The tubing handling device may serve for picking up and/or supportingany desired type of tubing, which may be a length of casing, liner,riser, drill tubing, production tubing or any other tubing utilised inthe industry. In place of electromagnets, any other suitable support maybe provided.

Where the rig assembly is for a surface facility, the surface facilitymay be an alternative vessel such as an FPSO or FSO, or a rig such as asemi-submersible, submersible or jack-up rig.

The rig floor receiving area may be provided on or in a frame or supportwhich may extend overboard.

Any desired rig floor unit may be provided, including suitablesupport/deployment apparatus or equipment.

The transporter may be configured to receive a plurality of selected rigfloor units. Thus, for example, where the rig assembly comprises threeor more rig floor units, the transporter may be configured to receivetwo units, for faster changeover.

Instead of being self-driven, a separate drive system may be providedfor moving the transporter/handling equipment.

1. A rig assembly comprising: a rig floor receiving area; a plurality ofmovable rig floor units, each rig floor unit configured for location inthe rig floor receiving area, to thereby define a rig floor of the rigassembly; and a transporter configured to receive any one of the rigfloor units, for transporting a selected one of the rig floor units froma storage area to the rig floor receiving area.
 2. A rig assembly asclaimed in claim 1, wherein the transporter is also for transporting arig floor unit from the rig floor receiving area to the storage area. 3.A rig assembly as claimed in claim 1, wherein each rig floor unit isadapted for performing a different task.
 4. A rig assembly as claimed inclaim 3, wherein each rig floor unit carries different equipment suitedto the particular task to be performed.
 5. A rig assembly as claimed inclaim 1, wherein the storage area comprises a plurality of rig floorstorage locations, each configured to receive a respective rig floorunit.
 6. A rig assembly as claimed in claim 1, wherein the transporteris movable along a path extending between the storage area and the rigfloor receiving area, for transporting the rig floor units between thestorage area and the rig floor receiving area.
 7. A rig assembly asclaimed in claim 1, wherein the rig floor units are each configured tobe releasably secured to the transporter.
 8. A rig assembly as claimedin claim 7, wherein at least one of the rig floor units and thetransporter comprise a locking assembly for securing the rig floor unitsrelative to the transporter.
 9. A rig assembly as claimed in claim 1,wherein the transporter is configured to be releasably secured withinthe rig floor receiving area.
 10. A rig assembly as claimed in claim 1,wherein the transporter is configured to be secured to a supportstructure provided in the rig floor receiving area.
 11. A rig assemblyas claimed in claim 10, wherein at least one of the transporter and thesupport structure comprise a locking assembly for securing thetransporter in the receiving area.
 12. A rig assembly as claimed inclaim 1, wherein the rig floor units are each configured to bereleasably secured within the rig floor receiving area.
 13. A rigassembly as claimed in claim 12, wherein the rig floor units are eachconfigured to be secured to a support structure provided in the rigfloor receiving area.
 14. A rig assembly as claimed in claim 13, whereinat least one of the rig floor units and the support structure comprise alocking assembly for securing the rig floor units in the receiving area.15. A rig assembly as claimed in claim 1, further comprising a transfersystem for transferring the rig floor units between a storage locationwithin the storage area and the transporter.
 16. A rig assembly asclaimed in claim 15, wherein the transfer system comprises a translationdevice for translating the rig floor units between their storagelocations and the transporter.
 17. A rig assembly as claimed in claim15, wherein the transfer system comprises a lift for raising and/orlowering the rig floor units between a level of the storage locationsand a level of the transporter.
 18. A rig assembly as claimed in claim1, wherein the transporter is shaped to straddle the rig floor units.19. A rig assembly as claimed in claim 5, wherein the transporter isheight adjustable for raising and lowering to a level of the unitstorage locations.
 20. A rig assembly as claimed in claim 1, furthercomprising tubing handling equipment coupled to and movable with thetransporter.
 21. A rig assembly as claimed in claim 20, wherein thehandling equipment comprises a tubing handling device for picking up andsupporting a length of tubing, and for transferring the tubing on to thetransporter.
 22. A rig assembly as claimed in claim 1, wherein thetransporter is for transporting the selected rig floor unit to alocation above a moonpool of a surface facility, for the deployment ofequipment into the moonpool.
 23. A rig assembly as claimed in claim 1,wherein the rig floor receiving area is adapted to be provided on aframe extending overboard from a surface facility.
 24. A rig assembly asclaimed in claim 1, wherein the rig floor units each comprise handlingapparatus for handling equipment to be deployed from the rig floor. 25.A rig assembly as claimed in claim 1, wherein the rig floor units areselected from the group comprising: a drill unit having a rotary drivefor driving and rotating a string of tubing; a BOP unit for supporting aBOP; a coiled tubing injector unit for supporting a coiled tubinginjector to be used for running coiled tubing; and a subsea shut-offdevice unit, for running a subsea shut-off device.
 26. A rig assembly asclaimed in claim 1, wherein at least one of the rig floor unitscomprises an aperture through which equipment may be deployed.
 27. A rigassembly as claimed in claim 1, comprising a support for supporting aload of a tubing string during changeover of rig floor units.
 28. A rigassembly as claimed in claim 1, wherein the transporter is configured toreceive a plurality of selected rig floor units simultaneously.
 29. Arig assembly as claimed in claim 1, wherein the transporter comprises adrive system for moving the transporter between the storage area and therig floor receiving area.
 30. A rig comprising a rig assembly, the rigassembly comprising a rig floor receiving area; a plurality of movablerig floor units, each rig floor unit configured for location in the rigfloor receiving area, to thereby define a rig floor of the rig assembly;and a transporter configured to receive any one of the rig floor units,for transporting a selected one of the rig floor units from a storagearea to the rig floor receiving area.
 31. A vessel comprising a rig, therig comprising a rig assembly, the rig assembly comprising a rig floorreceiving area; a plurality of movable rig floor units, each rig floorunit configured for location in the rig floor receiving area, to therebydefine a rig floor of the rig assembly; and a transporter configured toreceive any one of the rig floor units, for transporting a selected oneof the rig floor units from a storage area to the rig floor receivingarea.
 32. A method of providing a rig floor of a rig assembly, themethod comprising the steps of: providing a plurality of movable rigfloor units, each rig floor unit configured for location in a rig floorreceiving area of a rig assembly, the rig floor units located in astorage area on a rig; selecting one of the rig floor units; mountingthe selected rig floor unit on a transporter configured to receive anyone of the rig floor units; transporting the selected rig floor unitfrom the storage area to the rig floor receiving area using thetransporter; and locating the selected rig floor unit in the rig floorreceiving area, to thereby form a rig floor of the rig assembly.
 33. Amethod as claimed in claim 32, further comprising the steps of:returning the selected rig floor unit from the rig floor receiving areato the storage area using the transporter; selecting an alternative rigfloor unit; mounting the alternative rig floor unit on the transporter;transporting the alternative rig floor unit from the storage area to therig floor receiving area using the transporter; and locating thealternative rig floor unit in the rig floor receiving area, to therebyform an alternative rig floor of the rig assembly.
 34. A method asclaimed in claim 32, further comprising the steps of performing anoperation from the rig floor defined by the selected rig floor unit;returning the unit to the storage area; and, subsequent to locating thealternative unit in the receiving area, performing an operation from thealternative rig floor.
 35. A method as claimed in claim 32, furthercomprising securing the selected rig floor unit relative to thetransporter, transporting the selected rig floor unit to the receivingarea and then securing the transporter within the receiving area.
 36. Amethod as claimed in claim 32, further comprising securing the selectedrig floor unit within the receiving area and moving the transporter awayfrom the receiving area.
 37. A method as claimed in claim 32, furthercomprising storing the rig floor units in respective storage locationswithin the storage area, and transferring the units from their storagelocations on to the transporter using a transfer system.
 38. A movablerig floor unit, the rig floor unit configured for location in a rigfloor receiving area of a rig assembly to thereby define a rig floor ofthe rig assembly, the rig floor unit further configured to be receivedin a transporter for transportation from a storage area to the rig floorreceiving area.
 39. A rig floor transporter, the transporter configuredto receive any one of a plurality of rig floor units, for transporting aselected one of the rig floor units from a storage area to a rig floorreceiving area of a rig assembly.